The present disclosure relates generally to information handling systems, and more particularly to a power reporting offset system for voltage regulators in information handling systems.
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
Information handling systems such as, for example, servers, have begun incorporating processing systems that include processors that utilize real-time power measurement inputs with performance algorithms (e.g., Running Average Power Limit (RAPL) algorithms) that effect performance levels of the processor (e.g., “turbo” performance levels). In such servers, the processors typically rely on power measurements such as the monitored load current (Imon) from voltage regulators in the server (e.g., the voltage regulator that provides power to that processor) to regulate their performance level. However, current sensing components in voltage regulators vary in accuracy, resulting in often inaccurate reporting of the Imon from the voltage regulator to the processor, which then directly impacts the performance level of the processor. For example, processor manufacturers typically provide Imon tolerance target values (e.g., in voltage regulator pulse-width modulation (PWM) enabling specifications) that list the target accuracy for voltage regulator sensing components such as direct current resistance (DCR) sensors and metal-oxide semiconductor field-effect transistor (MOSFET) RDSon sensors, and those target accuracy values conventionally allow voltage regulator reporting of Imon that may be off by 4-5% at typical sustained load levels. As such, conventional Imon reporting can lead to different performance levels (e.g., turbo performance variation) across servers or even across processors in the same server.
Conventional solutions to the inaccurate Imon reporting discussed above include applying an offset to the Imon reported by the voltage regulator that results in a desired processor performance level of the processor. For example, if the processor is performing over a target performance level when provided a particular power level, a positive offset may be applied to the Imon reporting for that power level that indicates to the processor an increased power delivery and results in the processor reducing its performance. Similarly, if the processor is performing under a target performance level when provided a particular power level, a negative offset may be applied to the Imon reporting for that power level that indicates to the processor decreased power delivery and results in the processor increasing its performance. However, the offsetting of Imon reported by the voltage regulator to produce a desired processor performance level of the processor raises a number of issues.
For example, offsetting the Imon reported by the voltage regulator may affect the output voltage positioning of the voltage regulator that relies on the reported Imon (e.g., Vout=VID−(LL*Imon)). Furthermore, offsetting the Imon reported by the voltage regulator may affect maximum power detection due to the instantaneous Vout trip point being used to predict the maximum power inception point, which can also affect load profile control and system throttling. Further still, offsetting the Imon reported by the voltage regulator may shift load-line regulation, which introduces overshoot or undershoot issues during repetitive processor load transients. Further still, offsetting the Imon reported by the voltage regulator may affect over-current protection set points and result in the voltage regulator not being properly protected against a pre-set overcurrent inception point that allows the voltage regulator to withstand abnormally short excursions above peak current without failing. Further still, offsetting the Imon reported by the voltage regulator may affect auto-phase shedding add/drop thresholds and impact pre-optimized voltage regulator efficiency across the operational load range. These and other issues allow for only relatively small (e.g., ˜4%) offsets to be implemented, which limits the full potential of the processor and the ability to achieve maximum processor performance (e.g., “overclocking”) even when the system power and/or thermal capacity will support it, while effecting voltage regulator sizing and preventing optimal voltage regulator operation as well.
Accordingly, it would be desirable to provide an improved voltage regulator power reporting offset system.